This invention relates generally to current sources and more particularly to current sources adapted to produce current insensitive to temperature and external voltage supply variations.
As is known in the art, many applications require the use of a current source. Various types of current sources are described in Chapter 4 of Analysis and Design of Analog Integrated Circuits (Third Edition) by Paul R. Gray and Robert G. Meyer, 1993, published by John Wiley & Sons, Inc. New York, N.Y. As described therein, these current sources are used both as biasing elements and as load devices for amplifier stages. As is also known in the art, it is frequently desirable to provide a current source which is adapted to produce current insensitive to temperature and external voltage supply variations.